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| author | s-ol <s+removethis@s-ol.nu> | 2021-07-06 12:33:03 +0000 |
|---|---|---|
| committer | s-ol <s+removethis@s-ol.nu> | 2021-07-06 12:33:03 +0000 |
| commit | afff7616373801fdc4f5184d72a15b3160355cab (patch) | |
| tree | 34f159e97466f6acc42bade65dbcdd01ccf445ed | |
| parent | move other docs to rst as well (diff) | |
| download | subv-afff7616373801fdc4f5184d72a15b3160355cab.tar.gz subv-afff7616373801fdc4f5184d72a15b3160355cab.zip | |
fix hello_world comments
| -rw-r--r-- | hello_world.subv | 13 | ||||
| -rwxr-xr-x | qemu.sh | 2 |
2 files changed, 7 insertions, 8 deletions
diff --git a/hello_world.subv b/hello_world.subv index 60d9065..579a0e6 100644 --- a/hello_world.subv +++ b/hello_world.subv @@ -1,14 +1,13 @@ == code 0x80000000 - # load mhartid CSR into t0, trap all but first Hart - 73/system 5/rd/t0 2/funct3/csrrs 0/rs/x0 f14/imm12/mhartid - 63/branch 1/subop/!= 5/rs/t0 0/rs/x0 0/off13 + # trap all but first Hart (a0 = mhartid) + 63/branch 1/subop/!= a/rs/a0 0/rs/x0 0/off13 main: - # x4 = &message + # a0 = &message # . load high bits 37/lui a/rd/a0 Message/imm20hi # . add low bits - 13/opi 0/subop/add 4/rd/x4 a/rs/a0 Message/imm12lo + 13/opi 0/subop/add a/rd/a0 a/rs/a0 Message/imm12lo # call print 6f/jal 1/rd/ra print/off21 loop: @@ -19,7 +18,7 @@ print: # load 0x10010000 (UART0) into t0 37/lui 5/rd/t0 0x10010/imm20 print:loop: - # load unsigned byte at x4 + # load unsigned byte at a0 03/load 4/subop/byte 6/rd/t1 a/rs/a0 0/imm12 # break loop if zero 63/branch 0/subop/== 6/rs/t1 0/rs/x0 print:break/off13 @@ -29,7 +28,7 @@ print:spin: 63/branch 4/subop/< 7/rs/t2 0/rs/x0 print:spin/off13 # print char 23/store 2/width/word 5/rs/t0 6/rs/t1 0/off12 - # increment x4 + # increment a0 13/opi 0/subop/add a/rd/a0 a/rs/a0 1/imm12 # jump back up 6f/jal 0/rd/x0 print:loop/off21 @@ -1,2 +1,2 @@ #!/bin/sh -qemu-system-riscv32 -nographic -machine sifive_u -bios none -kernel "$@" +exec qemu-system-riscv32 -nographic -machine sifive_u -bios none -kernel "$@" |